Norman 494; Garrison-Morton 2483. FIRST EDITION, FIRST ISSUE, very rare. "Cohn's three papers, published in the journal that he founded and edited, are among the seminal works of bacteriology. The first paper (part I), originally published in 1872, effectively initiated the science: it contained Cohn's new system of bacteria classification, in which he distinguished four groups of bacteria based on their constancy of external form and linked this constancy to certain physiological phenomena. The second paper (part II) announced Cohn's discovery of thermoresistant spores produced by certain bacteria, which could survive even prolonged intense heat in a sealed container; this discovery explained what had long been a puzzling anomaly, and dealt a convincing blow to the doctrine of spontaneous generation." (Norman 494). A third part was published in 1876.